Waterless humidifier for residential and commercial furnaces

Abstract

A method and apparatus for humidifying residential and commercial buildings in which a flue gas generated by a residential or commercial furnace is provided to one side of a porous liquid water transport membrane and habitable space air is provided to an opposite side of the porous liquid water transport membrane in an amount sufficient to provide a habitable space air to flue gas volume flow rate ratio of at least 8.3:1. At least a portion of the water vapor in the flue gas is condensed, providing condensed liquid water which is passed through the porous liquid water transport membrane to the habitable space air side of the porous liquid water transport membrane. On the habitable space air side of the membrane, the condensed liquid water is evaporated into the habitable space air, producing humidified habitable space air which is provided to the rooms of the residential and commercial buildings. Beneficially, no supplemental water source is required for the humidification process.

We claim: 
     
       1. A method for humidifying a habitable space comprising the steps of:
 providing a water vapor-containing flue gas having a first water vapor partial pressure generated by one of a residential furnace and a commercial furnace to a flue gas side of a porous liquid water transport membrane; 
 providing habitable space air having a second water vapor partial pressure less than said first water vapor partial pressure to a habitable space air side of said porous liquid water transport membrane opposite said flue gas side in an amount sufficient to provide a habitable space air to flue gas volume flow rate ratio of at least 8.3:1; 
 condensing at least a portion of said water vapor in said flue gas in an interior of said porous liquid water transport membrane, forming liquid water in said interior in an amount sufficient to substantially prevent all gaseous components in said flue gas from passing through said porous liquid water transport membrane to said habitable space air side; 
 passing said liquid water to said habitable space air side of said liquid water transport membrane; 
 evaporating said liquid water on said habitable space air side into said habitable space air, producing humidified habitable space air; and 
 providing said humidified habitable space air to said habitable space. 
 
     
     
       2. The method of  claim 1 , wherein said habitable space air to flue gas volume flow rate ratio is in a range of about 8.3:1 to about 200:1. 
     
     
       3. The method of  claim 2 , wherein said habitable space air to flue gas volume flow rate ratio is in a range of about 40:1 to about 70:1. 
     
     
       4. The method of  claim 1 , wherein said habitable space air is at a temperature in a range of about 40° F. to about 100° F. 
     
     
       5. The method of  claim 4 , wherein said habitable space air is at a temperature in a range of about 60° F. to about 80° F. 
     
     
       6. The method of  claim 1 , wherein all of said humidified habitable space air is produced using only said water vapor in said flue gas. 
     
     
       7. The method of  claim 1 , wherein said porous liquid water transport membrane is in a form of a tube having an inside surface and an exterior surface. 
     
     
       8. The method of  claim 7 , wherein said inside surface corresponds to said flue gas side of said porous liquid water transport membrane and said exterior surface corresponds to said habitable space air side of said porous liquid water transport membrane. 
     
     
       9. The method of  claim 7 , wherein said inside surface corresponds to said habitable space air side of said porous liquid water transport membrane and said exterior surface corresponds to said flue gas side of said liquid water transport membrane. 
     
     
       10. The method of  claim 1 , wherein said porous liquid water transport membrane is disposed within a heated habitable space air conduit through which said humidified habitable space air is provided to said habitable space. 
     
     
       11. The method of  claim 1 , wherein said porous liquid water transport membrane is disposed in a habitable space air return conduit through which said habitable space air to be heated from said habitable space is provided to said one of said residential furnace and said commercial furnace for heating. 
     
     
       12. The method of  claim 1 , wherein said flue gas is at a higher temperature than said habitable space air, whereby a portion of heat energy in said flue gas is transferred to said habitable space air. 
     
     
       13. The method of  claim 1 , wherein said porous liquid water transport membrane has pore sizes less than about 50 μm or equal to about 50 μm.